Question

1. find the equation of the circle with center at (-3,1) and through the point (2,13)

2. what is the equation of the circle with the center at (2,4) and the radius of 6.

(show all work please and thank you)

Answer 1

Try this solution:
Common view of the equation of the circle is (x-a)²+(y-b)²=r², where point (a;b) is centre of the circle, r - radius.
1. using the coordinates of the centre and point (2;13) it is possible to define the radius of the circle: r=√(5²+12²)=13;
the equation is (x+3)²+(y-1)²=13² or (x+3)²+(y-1)²=169;
2. using the coordinates of the centre and the radius: (x-2)²+(y-4)²=6² or (x-2)²+(y-4)²=36.